Which of the anti-epileptic drugs affect the metabolism of the Pill (oral contraceptive) and what are the implications of this? Which drugs are safe to use in combination with the Pill? 

Phenobarbitone, phenytoin, carbamazepine, oxcarbazepine, Topiramate. These drug decrease the effectiveness of the contraceptives thus increase a women chance for a unplanned pregnancy.

It is safe for a women to use Valproate and lamotrigine, gabapentin, leviteracetam and vigabatrin with contraceptives.

Can oral contraceptives also affect the effectivity of the anti-epileptic drugs?

Yes, oral contraceptives decrease lamotrigine and valproate serum levels in the blood, thus effecting the effectiveness of these drugs.

How does age affect the kinetics of these drugs (from neonates to old age)?

Neonates’ metabolism is slower than adults and children thus they metabolised these drugs slower. But children’s metabolism is faster than adults thus dosage should be higher.

Geriatrics metabolise drug slower because they usually have a decreased renal function.

In which cases is plasma blood level monitoring indicated?

All cases because anti-epileptic drug has a small therapeutic index.